Optical broadcast networks (also known as all-broadcast optical networks) operate based on a wavelength being available on all links of the network, without cycles. The wavelength is broadcast through an Optical Broadcast Unit (OBU) which can be a 2×2, 3×3, N×N splitter/combiner. The wavelength is accessed as desired at different nodes in the network, but it is available at all nodes. One advantage of such networks is the switching fabric is low complexity/cost in terms of hardware, i.e. splitters and combiners only, and protection switching is quick, i.e. addition/removal of a wavelength blocking device. It is expected that such networks will proliferate in campus, metro, and/or regional optical networks with coherent modulation/demodulation technologies, such as with tunable receivers which can tune to any frequency of interest selectively. Examples of broadcast optical networks are described in commonly assigned U.S. Pat. No. 8,131,149 issued Mar. 6, 2012 and entitled “OPTICAL ROUTING DEVICE AND OPTICAL NETWORK USING SAME” and commonly assigned U.S. Pat. No. 8,554,074 issued Oct. 8, 2013 and entitled “COLORLESS, DIRECTIONLESS, AND GRIDLESS OPTICAL NETWORK, NODE, AND METHOD,” the contents of each are incorporated by reference herein. The optical broadcast networks can linear/star (hub and spoke)/tree topologies, with a constraint that cycles are not allowed in the topology, unless they contain the necessary switching or filtering functions to prevent wavelength interference. That is, one aspect of these networks is to selectively include a wavelength blocking element in the path to prevent such interference. Of note, the fundamental topology and operation of these networks is distinct from conventional architectures where a wavelength is directed between ingress and egress.
Networks at various layers are being deployed with control planes, Software Defined Networking (SDN), Network Functions Virtualization (NFV), and the like. Control planes provide automatic allocation of network resources in an end-to-end manner. Exemplary control planes may include Automatically Switched Optical Network (ASON) as defined in ITU-T G.8080/Y.1304, Architecture for the automatically switched optical network (ASON) (February 2012), the contents of which are herein incorporated by reference; Generalized Multi-Protocol Label Switching (GMPLS) Architecture as defined in IETF Request for Comments (RFC): 3945 (October 2004) and the like, the contents of which are herein incorporated by reference; Optical Signaling and Routing Protocol (OSRP) from Ciena Corporation which is an optical signaling and routing protocol similar to PNNI (Private Network-to-Network Interface) and MPLS; or any other type control plane for controlling network elements at multiple layers, and establishing connections therebetween. Control planes are configured to establish end-to-end signaled connections to route the connections and program the underlying hardware accordingly. SDN provides the management of network services through abstraction of lower-level functionality. This is done by decoupling the system that makes decisions about where traffic is sent (the control plane) from the underlying systems that forward traffic to the selected destination (the data plane).
Of note, optical broadcast networks exhibit different operational behavior and switching behavior from conventional optical networks, utilizing control planes. The aforementioned control planes and SDN do not contemplate operation with the optical broadcast networks. In optical broadcast networks, the bandwidth management function is not only on the link in the optical service route, but applies to all links in the network. This needs to be achieved in a distributed control plane environment. If a broadcast network integrates with a non-broadcast network (e.g., Reconfigurable Optical Add/Drop Multiplexer (ROADM), mesh, etc.) via switching points, bandwidth must be updated accordingly without breaking or modifying the network map view (topology). The optical broadcast network topology needs to be validated since it cannot support cycles without switching points. A horizontal synchronization (sync), as part of the control plane for node recovery (reboots) or link recovery (down to up) needs to allow for wavelength contention detection across a segmented broadcast network. Optimizations, in optical broadcast networks, also must permit retuning of wavelengths when contention is detected, such as in horizontal sync.